OpaqueMail includes a fully-featured test client that allows browsing and searching of IMAP and POP3 messages as well as sending of SMTP messages with encryption. It automatically embeds images into Text/HTML messages and strips Script tags.

It inherits from System.Net.Mail.MailMessage and System.Net.Mail.SmtpClient for simplified upgrades of existing code. OpaqueMail implements .NET 4.5 async and await.

OpaqueMail is designed to be the best .NET email library. It's thoroughly documented and optimized for security, usability, and performance.

Where we are and how we got here

Email was invented more than 40 years ago, before network security or privacy were common concerns. The original creators could never have predicted it would become the world's most popular communications medium.

Today, billions of people spend hours reading and composing emails every day. These range from personal messages to critical business communications. Everything travels through email, including sensitive information.

The overwhelming majority of emails are sent in "plain-text", meaning that everybody involved in sending your message can (and does) read it. And that's significantly more people than you'd expect.

The problem's even more serious when using an untrusted network, like the neighborhood coffee shop. Free tools allow anyone to snoop on unencrypted email traffic. That's unacceptable.

The solution already exists

"Public key cryptography" (a.k.a. asymmetric encryption) is the answer to secure messaging. This is the underlying technology behind SSL and TLS, which are used for everything from banking to military security.

Two standards have existed for mail encryption since the 1990s: S/MIME and OpenPGP. Both approaches work by encrypting email in a way that only the recipient can read. First, a "public key" is used to compose a secure message. Then, the recipient uses a "private key" (like a decoder ring) to decode the message.

Both OpenPGP and S/MIME are free, proven, and secure.

Let's fix that

The OpaqueMail project's goal is to normalize the use of email encryption. The first step is education, but we ultimately seek to make secure email the default option.

Let's get the word out.

First, spread the word about why email privacy matters and what we can do about it. We live in a critical time for defining and protecting our personal liberties online.

We all deserve freedom of speech and confidence that our communications are secure.

What's in a name?

Headlines in 2013 were dominated by "Prism", the US government's clandestine surveillance program. A prism refracts light, such as the fiber optics underlying the internet, allowing true colors to be studied individually.

"Opaque" is the opposite of "transparent", meaning that it's impenetrable to light. Opaque objects can't be refracted. OpaqueMail is resistant to Prism.